Fountain solution roller



v 1 1948. we; TOLAND ml. 2,453 13 FOUNTAIN sownon ROLLER Filed Jan. 18. 1945 Patented Nov, 16, 1948 FOUNTAIN SOLUTION ROLLER William Craig Toland, Brookline, and Munroe H.

Hamilton, Lexlngt Mass., assignors, by

mesne assignments, to William Craig Toland,

Brookline, Mass.

Application January 18, 1945, Serial No. 573,384

8 Claims. (Cl. 101-148) This invention relates to planographic printing and more especially to a water roller for applying an aqueous fountain solution to the surface of a planographic plate during the printing operation. The aqueous fountain solution thus applied maimtains the non-printing portions properly waterretentive and grease-repellent.

To further facilitate transfer of very limited quantities of the fountain solution to the plate surface, it is customary to employ a metal roll. usually brass, which is covered with a fabric commonly known as molleton." This fabric is required to be'sewed around the outer Periphery of the metal roller, an operation which is expensive and time-consuming. The life of the fabric on the press is relatively short. After a limited period of operation the fabric frequently develops a tendency to pick up small amounts of greas ink which may then be transferred to the non-printing portions of the printing plate, thus causing scumming, and a new fabric must be supplied.

An object of the invention therefore is to improve fountain solution rollers and to devise a coating and impregnating material which is of pronounced grease-rejecting character and which is adapted to reduce or substantially eliminate the occurrence of scumming when applied to a fountain solution roller. Another object is to provide a fountain solution roller element which is more e cient in applying aqueous materials; which is characterized by long life and which is cheap and easy to install. Other objects will appear from the following description.

In the accompanying drawings:

Fig. 1 is a perspective view illustrating a fountain solution roller of the invention; and

' illustrated a fountain solution roller l of some agent is a urea formaldehyde resin such as Plas- Fig. 2 is another perspective view illustrating a modification of the invention.

The invention generally includes a fountain solution roller covered with a water-receptive material which contains an agent such as a dib-asic acid, for maintaining th water-receptive material free from tiny particles of greasy ink of the type commonly employed in planographic printing.

We may .desire to apply the dibasic acid kon." Various other waterproofing resins and coating materials may be employed.

Numeral 4 denotes an outer coating in which is contained a dibasic acid such as oxalic acid. In forming the coating 4 the oxalic acid may be mixed with a water-receptive colloid such as, for example, gelatin, and it may also be desired to include a hardening agent for rendering the colloidal material tough and durable without loss of water-receptive character. Examples of hardening agents are formaldehyde, hexamethylenetetramine, chromium compounds and others. In place of oxalic acid we ma also utilize other dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid and th like.

The dibasic acid may be employed in varying amounts such as are illustrated by the following examples:

Example I '0 Oxalic acid gms 5 Gelatin mm 1 100 Water c..- 1000 Example II 0xalic acid gms 40 Gelatin mm 100 Water c 1000 Example III 0 Gelatin mm 100 Oxalic acid mm 25 Hexamethylenetetramine gms 50 Water c. c 1000 around the surface of the fountain solution roller in various ways as by applying it directly to the metal surface of the roller, or in conjunction with coverings such as fabrics, paper, plastic or. resinous substances utilized either in the form of a coating or a sleeve member which may be passed over the metal roller.

It has been found that the ability of a colloid, especially, to reject greasy ink and to provide for a limited degree of water-receptivity, may be greatly improved by using the dibasic acid. In addition the dibasic acid cooperates with hardening agents for the colloid, functioning to control 50 and modify the effect of the hardener on the colloid while remaining itself substantially unaffected by the hardener. Best results are obtained by using relatively large amounts of the chemical reagent and especially a .quantity or concen- For example, in Fig. 1 of the drawings we have tration which exceeds the amount of acid re- 3 agent required to maintain the colloid at its isoelecti'ic point. Thelatter term as employed herein denotes an acid pH value at which the colloid exhibits a maximum amount of swelling or waterreceptive character. The amounts of acidic reagent specified in Examples 11 and III are regarded as large in relation to the amount of colloid used and provide such an excess.

When relatively large amounts of a reagent such as the dibasic acid are used, unexpectedly good results are obtained in connection with preventing grease-retention on the roller surface. With fabric-covered rollers of the conventional type, small amounts of greasy ink gradually tend to accumulate on the fabric and later become transferred to the non-printing portions of a plate over which the roller is passed, thus producing an objectionable print. The presence of the dibasic acid described effectually prevents small amounts of grease from collecting on the surface of the roll throughout an extended period of use. The ability of the acid to exercise this function in conjunction with a hardening agent for the colloid provides for greatly increased durability of the colloid, and hence long and uninterrupted periods of operation with elimination of the expense and trouble attendant upon the use of stitched molleton covers.

During operation of a planographic printing press, the plate surface is conventionally supplied with small amounts of aqueous material containing a weak acid. If the surface of the printing plate acquires an alkaline pH value instead of an acid pH value, plate failure is very likely to take place. Having in mind the requirement for an acid pH value at a planographic printing plate surface, it is suggested that one action of a chemical reagent, such as oxalic acid or other dibasic acid, may be to become associated with the colloid on the colloid coating 4 on the roller, so that the reagent may tend to maintain an acid pH value which in turn maintains a sharp greaserepellent character at the surface of the roller, and indirectly at the non-printing portions of a printing plate over which the roller passes- It should be understood, however, that this explanation of the theory of operation of the dibasic acid, as well as any others appearing in the specification, are given by way of suggestion only and are not to be taken in a limiting sense.

The dibasic acid may be applied in other ways, 1

as for example that illustrated in Fig. 2 of the drawings, in which the acid is applied directly.

over the metal surface of the fountain solution roller I in conjunction with a water-receptive binder to form a coating 5. In such an'arrangement, the coating 5 is permanently aflixed to the core, as distin uished from the case of a roller such as illustrated in Fig. i, in which it is intended that the sleeve member 2 may be detachably secured to the core.

The core i may also be of plastic, fibrous materials, or other relatively stifl substances. In place of the colloid gelatin, we may desire to use other colloids or water-receptive binders, such as glue, gum arabic, polyvinyl alcohol and others. Similarly, other hardening agents may be employed in place of the hexamethylenetetramine or formaldehyde, as for example ferric chloride. A further modification may consist in the mixture of dibasic acid, colloid material and clays or other fillers. Another chemical reagent which may be desired to be employed consists of a mixture of a dibasic acid and a weak inorganic acid, as phosphoric acid. Still another regaent may consist of a mixture of a dibasic acid and a weak organic acid, such as gum arabic.

While we have described a preferred embodiment of our invention, it should be understood that various changes and modifications may be resorted to, without departing from the spirit of theinvention as defined in the appended claims.

We claim:

1. As an article of manufacture a roller for use in planographic printing, said roller being covered with a water-swellable material which includes a, water-soluble dibasic acid.

2. As an article of manufacture a water roller for use in planographic printing, said roller including an outer peripheral coating which includes a water-swellable colloid and a watersoluble dibasic acid, for maintaining the colloid grease-repellent.

3. As an article of manufacture a water roller for use in planographic printing, said roller presenting an outer peripheral body which includes a water-swellable colloidal material in which are incorporated solid portions of oxalic acid, said acid being soluble in water drawn into the colloidal material during swelling.

4. As an article of manufacture a water roller for use in planographic. printing, said-roller presenting an outer peripheral body which includes gelatin, a chemical hardener for the' gelatin and oxalic acid.

5. As an article of manufacture a water roller for use in planographic printing, said roller presenting an outer peripheral body which includes a water-swellable colloid, a hardener, and a water-soluble dibasic acid.

6. As an article of manufacture a water roller for use in planographic printing, said roller presenting an outer peripheral body which includes polyvinyl alcohol, oxalic acid and a hardener.

7. As an article of manufacture a water roller for use in planographic printing, said roller presenting an outer peripheral body which includes a glue, oxalic acid and a hardener.

V 8. As an article of manufacture a water roller for use in planographic printing, said roller presenting an outer peripheral body which includes gelatin, oxalic acid, and hexamethylenetetramine.

- WILLIAM CRAIG TOLAND.

MUNROE H. HAMILTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,712,077 Hrubesky et al. May 6, 1929 2,007,588 Wescott July 9, 1935 2,186,946 Wood Jan. 16, 1940 2,220,278 Rapport Nov. 5, 1940 

